1. Field of the Invention
Considerable research has been devoted to developing oil absorbents for cleanup of oil spills and removal of emulsified oil from waste water. Agricultural products and residues, such as kapok fiber, cotton, rice hulls, corn cob meal, bagasse fibers, and peat moss have been used for these applications, and these materials have the advantage of being inexpensive and readily available. Moreover, cellulosic products exist in fibrous form and can be easily formed into mats, pads, and nonwoven sheets. Mats and column packings for oil removal have also been prepared by mixing cellulosic fibers with synthetic fibers, e.g., polyethylene or polypropylene-polyethylene-nylon blend. Cellulosics have also been mixed with inorganic materials, such as clay, magnesium hydroxide, and alumina to give oil-absorbent compositions. This invention relates to enhancing the oil absorbencies of cellulosic materials by rendering them more hydrophobic; that is, more lipophilic.
2. Description of the Prior Art
The hydrophobicity of cellulosic materials (and thus their affinity for oil) has been increased by reaction with organic isocyanates (Holst et al., German Offen. 2,358,808) and with fatty acid derivatives, such as anhydrides (Ball et al, U.S. Pat. No. 3,770,575) and acid chlorides (Teng et al., U.S. Pat. No. 3,874,849). Also, Marx et al. (U.S. Patent No. 3,677,982) shows preparing an oil-absorbing cellulose-polystyrene composite by immersing a cellulose sponge into styrene-benzoyl peroxide and then heating the mixture to 100.degree. C.
Coating cellulosics with hydrophobic compounds, such as paraffin wax (Peterson et al., U.S. Pat. No. 3,630,891; Matsuda et al., Japanese Kokai 77/76,285; and Orth, German Offen. 2,301,176), insoluble fatty acid salts (Aoso et al., Japanese Kokai 74/64,577), or low melting polymers, such as polyolefins (Kunitomo et al., German Offen. 2,621,961; and Saida et al., Japanese Kokai 78/04,760) is another technique used to increase the affinity of fibers for oil; some polymers (e.g., ethylene-vinyl acetate copolymer) also have been deposited onto fibers from aqueous emulsions (Sato et al., Japanese Kokai 77/89,244; and Sato et al., Japanese Kokai 77/90,486).